A total knee replacement prosthesis assembly (10) comprising a femoral component (20), a tibial component (30) having a tibial platform (32), and a bearing component (40), the bearing component having an inferior side (40b) and a superior side (40a), the bearing component being adapted to be arranged between the femoral component and tibial platform when assembled,the tibial platform having a post (36) upstanding from it and the bearing component having a post recess (46) in its inferior side for receiving the post, the bearing component being rotatable about the post when assembled, the post and bearing component each having a transverse bore and the assembly further comprising an axle (60), at least part of the axle being received through the transverse bore (38) in the post when assembled and at least part of the axle being received through the transverse bore (52) in the bearing component when assembled, the axle being configured to provide an axis of rotation between the femoral component and bearing component which is fixed relative to the femoral component and the bearing component in use.
